Mixed clamping back-to-back multi-level AC-DC-AC switching circuit

Abstract

The invention discloses a mixed clamping back-to-back multi-level AC-DC-AC switching circuit. The mixed clamping back-to-back multi-level AC-DC-AC switching circuit comprises two groups of multi-level switching circuits and a direct current bus capacitor link connected with the two groups of multi-level switching circuits; and the level number of the direct current bus capacitor link is more than or equal to 4. By the mixed clamping back-to-back multi-level AC-DC-AC switching circuit, the dynamic self-balance between all direct current bus capacitors and clamping capacitors can be realized and equal capacitor voltage can be obtained so that the champing capacitors and the direct current bus capacitors complete multi-level boost output and a good condition for the expansion of the capacitance of direct current bus capacitors is created at the same time. The mixed clamping back-to-back multi-level AC-DC-AC switching circuit bears a high-power high-voltage load on the premise of guaranteeing system reliability and good harmonic output characteristics, is flexible in control, quite low in loss, has efficient performance, can realize bidirectional flow and mutual control compensation of reactive power and active power, and is very suitable for alternating current speed regulation or a power grid interconnection technique of different distributed power generating systems.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a hybrid clamp back-to-back multilevel AC-DC-AC (alternating current-direct current-alternating current) conversion circuit. Background technique [0002] Since its birth, the multi-level converter has won the attention of the industry and academia with its excellent boost expansion and power handling capabilities. Compared with other converters, multilevel converters can achieve higher DC voltage output by using multiple low-voltage devices, while avoiding the dynamic voltage equalization problem caused by series connection of devices. At the same time, multilevel converters also have many advantages such as high output voltage waveform quality, small harmonics, and low withstand voltage of switching devices. Therefore, multilevel AC-DC, DC-AC and AC-DC-AC conversion circuits are used in power Static var compensator and power active filter in the system, h...

AI Technical Summary

Problems solved by technology

[0004] The invention provides a hybrid clamp back-to-back multi-level AC-DC-AC conversion circuit, which overcomes the defect that the existing conversion circuit cannot guarantee system reliability and high-quality harmonic output characteristics when it is subjected to high-power and high-voltage loads , flexible control, low loss, high performance

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